1. Technical Field
The present invention relates to a liquid ejecting head, a liquid ejecting apparatus, and a piezoelectric element.
2. Related Art
Liquid ejecting heads are used as components of liquid ejecting apparatuses, for example, in ink jet printers. In such cases, the liquid ejecting heads are used for discharging droplets of ink and letting them fly. By doing so, the ink jet printers can perform printing by letting the ink adhere to printing media, such as paper.
The liquid ejecting heads usually have actuators for applying a voltage to liquid for discharging the liquid from nozzles. Some of these actuators have, for example, piezoelectric elements. The piezoelectric elements of the actuators may have a structure in which a piezoelectric body made of a piezoelectric material having an electromechanical conversion function, such as crystallized piezoelectric ceramics, is disposed between two electrodes. Such a piezoelectric element can deform by being applied with a voltage by the two electrodes and can operate the actuator, for example, in a deformation vibration mode by means of the deformation.
The piezoelectric material to be used in such an application preferably has high piezoelectric properties, such as electromechanical conversion efficiency. Since lead titanate zirconate (PZT) materials are excellent in the properties, compared to other materials, they have been researched and developed. However, recently, there has been a demand for further improving the piezoelectric properties of piezoelectric materials, and there is a requirement for using materials having less environmental loads. The PZT materials are difficult to meet these requirements, and, for example, perovskite-type oxides, which have low lead contents, have been developed as piezoelectric materials.
Some ceramic materials, which are logically thought to have high piezoelectric properties, are Bi-based oxides, for example, and it is currently known that BiFeO3 forms a perovskite-type crystal structure by being fired in a bulk form at ordinary pressure. Many of other Bi-based oxides form perovskite-type crystal structures at high pressure, higher than several gigapascals (Gpa), but do not form the perovskite-type crystal structures when they are fired under an atmosphere of ordinary pressure. For example, Bi(Zn0.5, Ti0.5)O3 (BZT) is known to form a perovskite-type crystal structure only when it is fired at high pressure (about 6 GPa).
JP-A-2009-256186 discloses a mixed oxide not containing alkali metals and lead. In JP-A-2009-256186, oxides having specific compositions have been evaluated for Curie temperatures, etc., and it is described that a piezoelectric material having an excellent piezoelectric property and a high Curie temperature can be provided.